Governor override for engine starting



Dec. 23, 1969 w, P K ET AL 3,485,228

GOVERNOR OVERRIDE FOR ENGINE STARTING Filed March 14, 1968 2 Sheets-Sheet 1 I 9 H f @A (Q 2; mm "25 21 29 Wx Q Q o IE- 37 o 35 49 all T is I3 INVENTORS KENNETH W. UPDYKE ALLAN J. FRIEDE AT TORNEYS United States Patent US. Cl. 123179 3 Claims ABSTRACT OF THE DISCLOSURE A coil heated thermostatic device actuates a plunger which mechanically deletes, during starting, the fuel pump rack limitation caused by a lack of intake manifold pressure or other similar signals.

This invention relates to a control for overriding the governor rack limiter by utilizing a thermostat in conjunction with a heating coil causing the rack limiter to be ineffective during starting.

Examples of engines having exhaust driven superchargers and utilizing rack limiters are shown in US. Patents 2,767,700 and 3,077,873 to Parks and assigned to the assignee of this application. The device is actuated by intake manifold pressure and is intended to limit the fuel pump rack position so as to avoid excess smoke during acceleration of the engine. The rack limiter has a spring which is preloaded to restrain the fuel pump rack in a decreased fuel position until intake manifold pressure is suflicient to support proper combustion, at which time it will overcome the force of the spring.

In a governor having a rack limiter, a lack of intake manifold pressure during starting causes the limiter to restrain a fuel pump rack in the decreased fuel position, necessitating an undesirable cranking time before sufiicient fuel becomes available to start the engine. During cold weather, starting becomes even more difiicult due to the decreased efficiency of the battery and cranking circuit.

A device for performing a function similar to the one performed by this invention is shown in US. Patent 3,313,283 to Miller and also assigned to the assignee hereof That device must be controlled by the operator and if the engine is remotely locatedsuch as in a vehicleit requires considerable linkage to make it accessible to the operator. In addition, it is not suitable for automatic start-stop operation.

Therefore, it is an object of this invention to provide an override control which may be utilized with the opera tor in a position distant from the engine and which will maintain the override condition prior to and during the starting cycle.

It is also an object of this invention to provide a governor override control which will allow sufiicient fuel to be delivered to the engine during starting while allowing normal governor operation when the engine is running.

It is a further object of this invention to provide a governor override control which restricts the rack limiter from engaging the rack during starting.

Other objects of the invention will become apparent to those sklled in the art upon perusal of the specification and drawings.

In the drawings:

FIG. 1 shows a schematic illustration of an engine utilizing the present invention and the electrical actuating circuitry;

FIG. 2 is a sectional view of the override control mounted on the governor body showing the interrelationship between the control and the governor and with the override control in its non-actuated condition;

FIG. 3 is an enlarged view of the override control with the control in a condition occurring after being actuated "ice but prior to its removal of the effect of the rack limiter;

FIG. 4 shows a view similar to FIG. 3 except that the control has moved the rack limiter shaft into a position in which it has no elfect on the fuel pump rack; and

FIG. 5 is a view of a ground spring device.

In greater detail, FIG. 1 shows an engine 11 having governor 13 with a rack limiter 15 and override control 17. The rack limiter is operatively connected with an engine intake manifold 19 by means of a fluid conduit 21. The control 17 is energized through a conductor 23 connected in parallel to a glow plug conductor 25, both of which are controlled by a switch 27 which also actuates the engine starting circuit (not shown).

Conductor 23 is attached to the control 17 at a suitable point such as shown at 29. Current passing through the conductor 23 also passes through a wire 31 connected to a heating coil 33 within the control. The heating coil is connected to a wire 35 which is suitably connected to a slotted ground spring 37.

At the end of the ground spring to which wire 35 is fixed, the spring is mounted on an insulating material 39. The other end of the spring, having a slot 41 therein as shown in FIG. 5, abuts head 43 of ground screw 45. As coil 33 heats, a thermostatic element or capsule 47 expands and extends an element 48 so as to move a plunger 49 outwardly against an end of rack limiter shaft 51.

The heating of the element and the resultant expansion thereof causes element 48 and plunger 49 to exert a pushing force against the end of shaft 51. As shown in FIG. 3, the initial resistance olfered by the shaft and its associated biasing means causes an assembly 53 to move to the left. This movement urges an end 61 of capsule 47 against a leaf spring 63 which causes the leaf spring to bow and push against ground spring 37 moving it away from the head of the screw 45. This breaks the circuit by removal of the ground contact.

With the circuit open, coil 33 loses heat but the heat absorbed by the capsule 47 continues to expand the thermostatic substance or element therein causing element 48 and plunger 49 to exert a force on shaft 51 which will overcome its biasing means moving it and the rack limiter to the position shown in FIG. 4. Therefore, as the engine is started, the fuel pump rack is free to be moved into a position which will allow increased fuel to be delivered to the engine.

As the capsule 47 cools, thereby retracting element 48, the plunger 49 will be retracted by a return spring 65 which is disposed between a shoulder 67 of plunger 49 and a washer or spring seat 69. The shoulder and spring seat are retained in place by the insulated portion 55 of the assembly 53. This allows shaft 51 to be biased back to the position shown in FIG. 2 so that the rack limiter is once again effective to control the fuel pump rack in accordance with the signal which controls it.

We claim:

1. In an engine governor having a fuel limiting means which controls and limits the quantity of fuel delivered to the engine in response to the strength of a signal derived from the operation of the engine, the improvement comprising a means for overriding said fuel limiting means including:

(a) a housing adjacent said governor,

(b) a heat expandable means in said housing and situated so as to control said fuel limiting means in response to heat it absorbs;

(0) means for dissipating electrical energy to generate heat within said housing so as to cause the expansion of said heat expandable means;

(d) means for discontinuing the operation of the means recited in (c) above upon expansion of said heat expandable means a first predetermined amount; and

(e) means associated with said heat expandable means References Cited tor motivating said fuel limiting means to a start- UNITED STATES PATENTS mg fuel position when said heat expandable means continues to expand to a second predetermined po- 2,195,927 4/1940 Hurst et sition in response to the heat it has absorbed prior to 2,825,321 3/1958 Anders -1 the operation of the means recited in (d) above. 5 3,089,475 5/1963 Kqhler et a1 123-179 2. The override means of claim 1 wherein said means 3,313,283 4/1967 Mlllef 12314O recited in (c) thereof comprises a coil which is energized for heat dissipation by an electrical signal passing therethrough. 10

3. The override means of claim 2 wherein said means recited in (d) thereof comprises a switch which is a por- LAURENCE M. GOODRIDGE, Primary Examiner tion of an electrical circuit through which said electrical signal passes, said switch being opened by expansion of said heat expandable means to said first predetermined 15 amount.

FOREIGN PATENTS 529,671 11/1940 Great Britain. 

